St Kilda SAC

Status: Designated


Site overview

This site is an archipelago west of the Outer Hebrides and is made up of wave-exposed reefs. There are kelp forests here, along with diverse communities of anemones, sponges and soft corals.  There is one of the most extensive sea cave systems in the UK here. The cave walls are blanketed only by sponges. Rarely recorded nocturnal species have also been found in the inner caves, including types of crab and anemones.

MPA Type

Special Area of Conservation

Special Areas of Conservation (SACs) are strictly protected sites designated under European legislation. They contribute both to the UK MPA network and set up to protect habitat types and species considered to be most in need of conservation at a European level (excluding birds).

Designation date

1 October 1996

Surface Area

253.92 km2 (98.04 mi.2)


63.81 km (39.65 mi.)

  • Submerged or partially submerged sea caves

    Typically associated with reefs, caves that are either underwater all the time or welcome the sea at high tides, caves provide a habitat for a wide variety of plants and animals.

  • Reefs

    Areas where the bedrock, stable boulders and cobbles or structures created by animals arise from the surrounding seabed. They attract and provide a home to a huge variety of plant and animal life.

Seasearch Logo

A real ‘bucket list’ area for divers, Seasearch data does exist from St Kilda but in small quantities since it requires excellent conditions to visit the archipelago.

Learn more about Seasearch

Did you know?…

Over half a million people have voiced their support for ‘marine protected area’ designation in the UK through our campaigns

An area over 9 times the size of Wales is now in marine protected areas in the UK, but less than 1% is considered by MCS scientists to be well managed

Over 500,000 records on undersea habitats and species have been collected by volunteer Seasearch divers providing significant evidence for inshore ‘marine protected areas’